People generally interact with computers through a keyboard and a mouse to enter alphanumeric data such as text, and/or to identify objects of interest on a computer screen. On the other hand, people commonly interact with one another by using gestures, for example, by shaking one's head to indicate “no”, or by pointing to an object of interest. Gesturing and using body language are often faster methods of transmitting data than pressing buttons, operating joy sticks, writing, and talking. Gestures and body language convey pictures. The human mind processes pictures much faster than it processes written or audible strings of words, and communicating by gesturing is a natural and preferred method of interfacing with other people and rapidly transmitting to them relatively large amounts of data. How many written or voiced words might be required to transmit the information in a frown, a skewed smile, a raised eyebrow, or a dismissive throw of the hand? And how long would it take to decode the words?
As computers and computer aided devices, such as household appliances, gaming consoles, and industrial equipment, have become ever more common and natural features of the modern environment, communicating with them, and through them, has become incessant. Communicating through keyboards and mice for an increasing number of applications often appear too slow and encumbering. Communicating with them by gesturing may increase speed and ease with which people can transmit data to them, “feels” natural, and has become increasingly attractive. However, computers are not animate and do not “read” people like people read people, and configuring effective and comfortable human-machine interfaces that support entering data to a computer by gesturing has proven to be challenging.